SqlBulkCopyColumnMapping Class

 

Defines the mapping between a column in a SqlBulkCopy instance's data source and a column in the instance's destination table.

Namespace:   System.Data.SqlClient
Assembly:  System.Data (in System.Data.dll)

System.Object
  System.Data.SqlClient.SqlBulkCopyColumnMapping

Public NotInheritable Class SqlBulkCopyColumnMapping

NameDescription
System_CAPS_pubmethodSqlBulkCopyColumnMapping()

Default constructor that initializes a new SqlBulkCopyColumnMapping object.

System_CAPS_pubmethodSqlBulkCopyColumnMapping(Int32, Int32)

Creates a new column mapping, using column ordinals to refer to source and destination columns.

System_CAPS_pubmethodSqlBulkCopyColumnMapping(Int32, String)

Creates a new column mapping, using a column ordinal to refer to the source column and a column name for the target column.

System_CAPS_pubmethodSqlBulkCopyColumnMapping(String, Int32)

Creates a new column mapping, using a column name to refer to the source column and a column ordinal for the target column.

System_CAPS_pubmethodSqlBulkCopyColumnMapping(String, String)

Creates a new column mapping, using column names to refer to source and destination columns.

NameDescription
System_CAPS_pubpropertyDestinationColumn

Name of the column being mapped in the destination database table.

System_CAPS_pubpropertyDestinationOrdinal

Ordinal value of the destination column within the destination table.

System_CAPS_pubpropertySourceColumn

Name of the column being mapped in the data source.

System_CAPS_pubpropertySourceOrdinal

The ordinal position of the source column within the data source.

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

Column mappings define the mapping between data source and the target table.

If mappings are not defined—that is, the ColumnMappings collection is empty—the columns are mapped implicitly based on ordinal position. For this to work, source and target schemas must match. If they do not, an InvalidOperationException will be thrown.

If the ColumnMappings collection is not empty, not every column present in the data source has to be specified. Those not mapped by the collection are ignored.

You can refer to source and target columns by either name or ordinal. You can also mix by-name and by-ordinal column references in the same mappings collection.

The following example bulk copies data from a source table in the AdventureWorks sample database to a destination table in the same database. Although the number of columns in the destination matches the number of columns in the source, and each destination column is in the same ordinal position as its corresponding source column, the column names do not match. SqlBulkCopyColumnMapping objects are used to create a column map for the bulk copy.

System_CAPS_importantImportant

This sample will not run unless you have created the work tables as described in Bulk Copy Example Setup. This code is provided to demonstrate the syntax for using SqlBulkCopy only. If the source and destination tables are in the same SQL Server instance, it is easier and faster to use a Transact-SQL INSERT … SELECT statement to copy the data.

Imports System.Data.SqlClient

Module Module1
    Sub Main()
        Dim connectionString As String = GetConnectionString()

        ' Open a connection to the AdventureWorks database.
        Using sourceConnection As SqlConnection = _
           New SqlConnection(connectionString)
            sourceConnection.Open()

            ' Perform an initial count on the destination table.
            Dim commandRowCount As New SqlCommand( _
            "SELECT COUNT(*) FROM dbo.BulkCopyDemoDifferentColumns;", _
                sourceConnection)
            Dim countStart As Long = _
               System.Convert.ToInt32(commandRowCount.ExecuteScalar())
            Console.WriteLine("Starting row count = {0}", countStart)

            ' Get data from the source table as a SqlDataReader.
            Dim commandSourceData As SqlCommand = New SqlCommand( _
               "SELECT ProductID, Name, ProductNumber " & _
               "FROM Production.Product;", sourceConnection)
            Dim reader As SqlDataReader = commandSourceData.ExecuteReader

            ' Set up the bulk copy object.
            Using bulkCopy As SqlBulkCopy = New SqlBulkCopy(connectionString)
                bulkCopy.DestinationTableName = _
                "dbo.BulkCopyDemoDifferentColumns"

                ' Set up the column mappings by name.
                Dim mapID As New _
                  SqlBulkCopyColumnMapping("ProductID", "ProdID")
                bulkCopy.ColumnMappings.Add(mapID)

                Dim mapName As New _
                 SqlBulkCopyColumnMapping("Name", "ProdName")
                bulkCopy.ColumnMappings.Add(mapName)

                Dim mapMumber As New _
                 SqlBulkCopyColumnMapping("ProductNumber", "ProdNum")
                bulkCopy.ColumnMappings.Add(mapMumber)

                ' Write from the source to the destination.
                Try
                    bulkCopy.WriteToServer(reader)

                Catch ex As Exception
                    Console.WriteLine(ex.Message)

                Finally
                    ' Close the SqlDataReader. The SqlBulkCopy
                    ' object is automatically closed at the end
                    ' of the Using block.
                    reader.Close()
                End Try
            End Using

            ' Perform a final count on the destination table
            ' to see how many rows were added.
            Dim countEnd As Long = _
                System.Convert.ToInt32(commandRowCount.ExecuteScalar())
            Console.WriteLine("Ending row count = {0}", countEnd)
            Console.WriteLine("{0} rows were added.", countEnd - countStart)

            Console.WriteLine("Press Enter to finish.")
            Console.ReadLine()
        End Using
    End Sub

    Private Function GetConnectionString() As String
        ' To avoid storing the sourceConnection string in your code, 
        ' you can retrieve it from a configuration file. 
        Return "Data Source=(local);" & _
            "Integrated Security=true;" & _
            "Initial Catalog=AdventureWorks;"
    End Function
End Module

.NET Framework
Available since 2.0

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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